Pubdate: Sun, 13 May 2007
Source: Independent  (UK)
Copyright: 2007 Independent Newspapers (UK) Ltd.
Contact:  http://www.independent.co.uk/
Details: http://www.mapinc.org/media/209
Author: Jonathan Owen and Sophie Goodchild

DIY KIT WILL SHOW MENTAL HEALTH DANGERS OF CANNABIS

Experts Isolate Gene Associated With Schizophrenia Risk

Scientists are developing a revolutionary test to identify people at
risk of cannabis-induced schizophrenia.

Experts at the Institute of Psychiatry in London have been able to
isolate a type of gene found in people who are five times more likely
to become mentally ill from using the drug.

GPs hope to use the simple and inexpensive mouth swab test as an early
warning system for vulnerable patients.

Until now, it has been impossible to predict who is at greatest risk
of mental illness from the drug, unless there is already a family
history of schizophrenia.

However, Dr Marta Di Forti, a clinical researcher at the Institute of
Psychiatry, said that screening could benefit young people as well as
their parents who may be worried about the effect of cannabis on their
children's mental wellbeing.

"Screening could really help parents in the future who may be worried
about their children," said Dr Di Forti, a psychiatrist who is
conducting a three-year study into genetics and psychosis. We don't
want to raise their expectations because we are not at the stage where
we can market this and say that if you have this variant you're safe
and this one you're not, but you might be able to use DNA screening to
predict vulnerability in the future.

"One of the reasons some people using cannabis develop schizophrenia
could be related to genetic susceptibility."

This comes amid increasing concern over the risks associated with
cannabis use. Although experts are divided, there is growing evidence
that parts of the population are at risk of developing mental illness
from cannabis use.

A 10-year study, published last month, revealed that people who start
using cannabis as teenagers are more likely than drinkers to suffer
from mental illness and also more likely to develop relationship problems.

The findings from Australian researchers were based on the experiences
of 1,900 schoolchildren. Experts have now discovered that cannabis can
disrupt brain function.

Tests on human volunteers given THC, the active ingredient in
marijuana, had significantly reduced activity in the frontal lobe - a
part of the brain responsible for co-ordination and emotional behaviour.

It is still unclear exactly how cannabis can trigger psychosis but it
is thought that the drug raises the brain's levels of dopamine - a
chemical that transmits signals between nerve cells and is associated
with schizophrenia.

As many as one in four Britons is at increased risk of developing
cannabis-related mental health problems. They have what is known as a
"val val" variant of the gene that regulates dopamine levels, compared
with those of the "met met" type who have no increased risk.
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MAP posted-by: Derek